This is an image of how the Gulf Stream kept Europe warm in the past. This summer the North Atlantic Current, which normally flows up around the North of Scotland into the Norwegian sea, dropped down South, to flow South-East. If the Jet Stream would stay where it is, would a large part of Europe freeze this coming winter? 
I don't know why Weather Modification pops into my mind? In a sense we are modifying the weather through unclean industrial processes. Of course, drought and desertification of Europe would lead to mass famine. In some ways heavy rain is preferable to no rain at all. There is always a balanced way to do things or one can act in a fragmented, unbalanced way. It is not WHAT you do, but the WAY that you do it. Either we are part of nature, working together - or we are outside nature trying to control those magnificent forces.
"Technology will make available, to the leaders of major nations, techniques for conducting secret warfare, of which only a bare minimum of the security forces need be appraised…Technology of weather modification could be employed to produce prolonged periods of drought or storm." - Zbigniew Brzezinski, Between Two Ages.
I feel that we will have to cooperate to protect the earth from this kind of abuse. The weather is a phenomenon that is open to all people and all nations. The weather is not a weapon... Although Zecharia Sitchin suggested in his translations of the Sumerian tablets that the weather was used/manipulated 'by the gods' to control human populations. To use the weather as a weapon of mass destruction goes against the core values of what the weather actually is. I don't really see that humans can get away with this. It will obviously backfire.
There would have to be an International agreement that any attempt to use the weather against other nations is a crime against all humanity.
BBC News - Financial Times - Guardian Unlimited - Weather Modification
